Answer:
C, Is is the answer.
Explanation:
Would be is past tense,
Were too is past tense
Is is present tense and so is the sentence
Are does not sound right in the sentence
<span>When the boys started hurting each other. They were acting like uncivilized, brutal, cruel, barbaric animals. </span>
Photosynthesis produces oxygen and glucose mainly. The oxygen gets released into the air, because oxygen to plants is like carbon dioxide to us. It doesnt harm them, but they cant use it. The glucose ends up either being used by the plant or stored somewhere within the plant to be used later.